Bypass mechanisms for energy generation systems

1. A photovoltaic (PV) module string for an energy generation system comprising:

a plurality of PV module sub-circuits, each PV module sub-circuit of the plurality of PV module sub-circuits comprising:

a plurality of PV sub-modules coupled together via external cables, the plurality of PV sub-modules comprising a first PV sub-module and a second PV sub-module;

a negative output terminal coupled to the first PV sub-module of the plurality of PV sub-modules;

a positive output terminal coupled to the second PV sub-module of the plurality of PV sub-modules;

a plurality of connectors external to the PV sub-modules and coupling the PV sub-modules together to form the PV module sub-circuit so that a current flows through the connectors and the external cables during energy generation; and

a sub-circuit bypass mechanism comprising a first terminal coupled to only the negative output terminal and the first PV sub-module, and a second terminal coupled to only the positive output terminal and the second PV sub-module, the sub-circuit bypass mechanism configured to prevent current flow in a first direction and allow current flow in a second direction opposite of the first direction when a voltage across the sub-circuit bypass mechanism increases above a first voltage threshold to prevent an occurrence of a thermal event; and

a system bypass mechanism coupled to the negative output terminal of a first PV module sub-circuit of the plurality of PV module sub-circuits and to the positive output terminal of a second PV module sub-circuit of the plurality of PV module sub-circuits, the system bypass mechanism configured to prevent current flow in a third direction and allow current flow in a fourth direction opposite of the third direction when a voltage across the system bypass mechanism increases above a second voltage threshold.

2. The PV module string of claim 1 , wherein the sub-circuit bypass mechanism is a passive electrical device.

3. The PV module string of claim 2 , wherein the passive electrical device is a diode.

4. The PV module string of claim 3 , wherein an anode of the diode is coupled to the negative output terminal and a cathode of the diode is coupled to the positive output terminal.

5. The PV module string of claim 1 , wherein the bypass mechanism is an active electrical device.

6. The PV module string of claim 5 , wherein the bypass mechanism is a power electronic circuit.

7. The PV module string of claim 6 , wherein the power electronic circuit comprises a sensor, a switch, and a controller coupled to the sensor and the switch and configured to control the switch based on data received from the sensor.

8. The PV module string of claim 6 , wherein the power electronic circuit is incorporated in an optimizer for performing maximum power point tracking of power outputted by the plurality of PV sub-modules.

9. The PV module string of claim 1 , wherein each of the PV sub-modules comprises at least two PV cells.

10. The PV module string of claim 1 , wherein the PV sub-module is a PV shingle that has a structure and an appearance of a roof shingle.

11. The PV module string sub-circuit of claim 1 , wherein the thermal event is an occurrence of an electrical arcing or overheating.

12. A building-integrated photovoltaic (PV) energy generation system comprising:

a plurality of PV module sub-circuits coupled together and configured to output power to a pair of terminals, each PV module sub-circuit comprising:

a plurality of PV sub-modules coupled together via external cables, the plurality of PV sub-modules comprising a first PV sub-module and a second PV sub-module;

a negative output terminal coupled to the first PV sub-module of the plurality of PV sub-modules;

a positive output terminal coupled to the second PV sub-module of the plurality of PV sub-modules;

a plurality of connectors external to the PV sub-modules and coupling the PV sub-modules together to form the PV module sub-circuit so that a current flows through the connectors and the external cables during energy generation; and

a sub-circuit bypass mechanism comprising a first terminal coupled to only the negative output terminal and the first PV sub-module, and a second terminal coupled to only the positive output terminal and the second PV sub-module, the bypass mechanism configured to prevent current flow in a first direction and allow current flow in a second direction opposite of the first direction when a voltage across the sub-circuit bypass mechanism increases above a voltage threshold;

a system bypass mechanism coupled to the negative output terminal of a first PV module sub-circuit of the plurality of PV module sub-circuits and to the positive output terminal of a second PV module sub-circuit of the plurality of PV module sub-circuits, the system bypass mechanism configured to prevent current flow in a third direction and allow current flow in a fourth direction opposite of the third direction when a voltage across the system bypass mechanism increases above a second voltage threshold; and

an inverter coupled to the plurality of PV module sub-circuits via the pair of terminals and configured to receiver power from the plurality of PV module sub-circuits.

13. The energy generation system of claim 12 , wherein the sub-circuit bypass mechanism is a diode.

14. The energy generation system of claim 13 , wherein an anode of the diode is coupled to the negative output terminal of the PV module sub-circuit and a cathode of the diode is coupled to the positive output terminal of the PV module sub-circuit.

15. The energy generation system of claim 12 , wherein the sub-circuit bypass mechanism is a power electronic circuit.

16. The energy generation system of claim 15 , wherein the power electronic circuit comprises a sensor, a switch, and a controller coupled to the sensor and the switch and configured to control the switch based on data received from the sensor.

17. The energy generation system of claim 12 , wherein each of the PV sub-modules comprises at least two PV cells.

18. The energy generation system of claim 12 , wherein each of the PV sub-modules is a PV roof tile that has a structure and an appearance of a roof tile.

19. The energy generation system of claim 12 , wherein the sub-circuit bypass mechanism is configured to prevent an occurrence of a thermal event caused by electrical arcing or overheating.